Most people know that concrete is made of water, cement, and aggregate, but most concrete poured today has a lot more going on behind the scenes (and beneath the surface) with admixtures playing a crucial role.
From photorealistic walls to plazas poured in cold weather, the secret to great concrete isn’t just in the finish—it’s in the mix. That’s where concrete additives, or admixtures, come in.
We’re not chemists (and don’t pretend to be), but we know how to collaborate with the right people—engineers, suppliers, and technical experts—to make sure the mix fits the project. This article highlights some of the most common—and a few lesser-known—additives we use to make our concrete perform at its best.
Side note: Even without admixtures, we can adjust the cement content, aggregate size, fine-to-coarse ratio, and water levels. But admixtures give us even more control and flexibility.
What Are Admixtures?
Concrete admixtures are ingredients added to the mix—beyond the basics of cement, water, and aggregate—to enhance performance, improve workability, and fine-tune how the concrete behaves in specific conditions.
Some are chemical, like water reducers or accelerators, and others are mineral, like fly ash or slag. Depending on the project, we may use one or a combination.
Our Most-Used Admixtures
Air Entrainment
Creates tiny bubbles in the mix, improving durability in freeze-thaw climates (Colorado winters).
Think of it as built-in shock absorption for fluctuating temperatures.
Water Reducers / Plasticizers
These reduce the amount of water needed in the mix without sacrificing flow. The result? Stronger concrete, less shrinkage, and smoother placement.
Available in low-, mid-, and high-range types depending on the slump (flowability) we’re after.
Ideal for tight forms or intricate placements without weakening the mix.
Accelerators & Retarders
Control how quickly concrete sets—speeding it up in cold weather or slowing it down in the heat to give us more working time.
Fibers
Tiny reinforcements dispersed throughout the mix to help reduce cracking and improve durability—especially in thinner or suspended slabs.
Color Additives
Integral pigments are added directly into the mix for bold, long-lasting color. We typically use the Davis Colors chart with shades like Sunset Rose, San Diego Buff, and Adobe.
Comes in powder, liquid, or pellet form, and colors the entire depth of the slab.
Spotlight on SCC (Self-Consolidating Concrete)
SCC is a specialized, highly fluid mix that flows into forms without mechanical vibration—ideal for intricate shapes and detailed surface finishes.
What Makes SCC Work:
Higher Cement + Pozzolan Content: Boosts durability, lowers permeability, and increases long-term strength.
VMA (Viscosity Modifying Admixture): Keeps the mix cohesive, avoiding aggregate segregation.
HRWR (High-Range Water Reducer): Improves flow without increasing water.
Refined Aggregate Blend: Smaller, well-graded particles enhance workability.
The Result:
SCC is smooth, self-leveling, and delivers crisp surface detail with less labor. We use it frequently for architectural features and form-finished walls where precision and finish are key.
Other Additives We Use When the Project Calls for It
These aren’t in every mix, but when we need them, they make a big difference:
Shrinkage Reducers: Help minimize cracking during the curing process.
Internal Curing Agents: Promote even hydration from within the slab. Especially helpful for shotcrete pool shells, where external curing can be tricky.
Waterproofing Additives: Used for splash pads, water features, and water-retaining structures.
Corrosion Inhibitors: Protect embedded steel, especially in coastal or freeze-prone environments. Not often specified in our work, but worth knowing about.
MVRA (Moisture Vapor Reduction Agents): Useful for slabs where flooring will be installed shortly after the pour, to control vapor transmission.
So, Why Does This Matter?
No two projects are alike. We pour concrete year-round, in all types of weather, and for a wide variety of applications—from city sidewalks to decorative vertical walls. Whether we’re racing the clock on a hot summer day or fine-tuning a high-end architectural surface, having the right admixture—or mix of them—can make all the difference.
At Colorado Hardscapes, we partner closely with ready-mix suppliers and technical consultants to customize every mix we pour. That’s the kind of behind-the-scenes detail that turns good concrete into great concrete.
Got Questions? We’ve Got People.
Not sure which type of concrete your project needs? Let’s talk. We’re always happy to share what we know—or connect you with one of our trusted technical experts for deeper guidance.
